The present invention relates to a heat exchanger, especially to an oil cooler for vehicles.
Such oil coolers are typically used for cooling of engine oil, for instance in an oil/oil cooler or in an oil/water cooler. As is for example described in DE 103 49 141 A1, such oil coolers are often designed as heat exchangers with stacked plates. To this end, the oil cooler comprises a heat exchanger element with individual stacked plates. The passages created between adjacent plates define the flow channels of both fluid media: The medium releasing heat and the medium taking up heat. Additionally, turbulizers or fins may be inserted between the stacked plates, to serve as heat transfer augmentation or structural support devices. The stacked plates are connected to each other, especially by brazing. Typically the plates are made of a metal that provides pre-placed filler metal for brazing, for example aluminum brazing sheet. Such a heat exchanger may however also have a completely different configuration, e.g. pairs of individual plates may have parallel flanged edges that are similarly joined by brazing, that may be ribbed or dimpled in form or again contain turbulizers inserted between them, and that when stacked together may be contained within a housing.
The stacked plate heat exchangers as described above comprise—at least on one of the termini of the stack—an end plate with inlets and outlets for media. In addition to the end plate, such conventional oil heat exchangers comprise a flange plate, also referred to as a mounting plate, or a facial base plate, by which the oil heat exchanger is sealingly mounted on a part, such as an engine or another part, in such a way that communication means are established for the fluid media to be transferred between the engine or other part, and the heat exchanger inlets and outlets. This flange plate is typically brazed onto the heat exchanger during the heat exchanger assembly process, again to maintain sealed fluid media communication passageways to the heat exchanger stack.
Because the oil supply system in many internal combustion engines involves relatively high pressure cyclic loads, often in combination with induced vibration loads, the flange or facial base plate must be very rigid to minimize deflection forces on the attached heat exchanger stack; and to maintain seal integrity. This often requires the use of heavy gauge metal flange plates, which complicate brazing due to the mass differences between the facial base plate, and the much thinner gauge heat exchanger plates. Also, since elastomer sealing materials cannot survive the brazing temperatures during heat exchanger assembly, subsequent attachment of the flange plate to the engine or other receiving part requires the use of separately applied gasket components.
Such a conventional oil heat exchanger thus requires a laborious sealing in order to guide the medium in a media-tight manner at the connections between the supplying pipes and the oil cooler, especially its end plate. This leads to a complex construction which requires a lot of parts and is cumbersome to be mounted. Furthermore, the use of heavy gauge metal flange plates is costly in material, and adds significant complexity to the heat exchanger brazing process.